Lateral vibration characteristics of an extended pile shaft under low-strain integrity test: Fid-Bau Portal

Lateral vibration characteristics of an extended pile shaft under low-strain integrity test

Wu, Juntao / El Naggar, M. Hesham / Wang, Kuihua / Wu, Wenbing

Abstract The integrity of extended pile shaft is paramount for ensuring safe and acceptable performance of supported bridge structures. However, it is difficult to conduct the vertical excitation low-strain integrity test for an extended pile shaft that supports an existing bridge. This paper investigates the feasibility of employing lateral low-strain test to predict the pile length of an extended pile shaft. An analytical model is developed to simulate the behavior of a pile, partially embedded in soil, with a pile cap and superstructure under a lateral low-strain excitation. Considering the frequency spectrum of an impulse excitation, the developed model employs the modified Timoshenko beam theory to accurately simulate the lateral pile vibration accounting for both rotary inertia and shear. The analytical solution is then utilized to analyze the dispersion of the pile-soil system when subjected to the lateral excitation. The effects of pile and soil properties on the pile dynamic response and wave propagating velocity are investigated through a comprehensive parametric study. A simplified method is proposed to approximately evaluate the pile length of this case on site.

Highlights • This paper investigates the feasibility of employing lateral PIT to predict the pile length of an extended pile shaft. • An analytical model is developed to simulate the behavior of a pile under a lateral low-strain excitation. • The dispersion of the developed model has been investigated. • We proposed a lateral PIT on site: the excitation is imposed at pile near the ground, the sensor is placed near the pile top.